CN111910621A - Structure for cooling frozen soil by combining cast-in-place bored concrete pile in perennial frozen soil area with heat pipe - Google Patents

Abstract

The invention relates to a structure for cooling permafrost soil with cast-in-place piles combined with heat pipes. The structure includes cast-in-place piles placed in the permafrost layer and heat pipes with working fluids inside. The lower evaporation section of the heat pipe is buried in the cast-in-place pile, and the upper condensation section is arranged between the ground surface and the building; the upper part of the heat pipe is provided with a radiator. The invention has a simple structure and is easy to implement, and can significantly reduce the temperature of the pile foundation and the permafrost layer where the pile foundation is located by virtue of the working characteristics of the heat pipe, thereby preventing the settlement of the pile foundation.

Description

A structure of permafrost area cast-in-place pile combined with heat pipe to cool the frozen soil

technical field

The invention relates to the field of permafrost region engineering, in particular to a structure for cooling the frozen soil by combining a cast-in-place pile in a permafrost region with a heat pipe.

Background technique

In permafrost regions, cast-in-place piles are the most common building foundation solutions in permafrost regions. However, the settlement of pile foundations often occurs due to the warming or thawing of frozen soil, and the volume of ice in the frozen soil becomes smaller after melting. It sinks itself, and the frozen soil loses its original bearing capacity after thawing, resulting in the settlement of the pile foundation, and finally the uneven deformation of the building foundation or other engineering foundations, which will cause damage to the building and cannot be used.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a structure that solves the problem of pile foundation settlement caused by permafrost thawing that often occurs in permafrost regions, combined with heat pipes to cool the frozen soil.

In order to solve the above problems, the present invention provides a structure of a permafrost area cast-in-place pile combined with a heat pipe to cool the frozen soil, characterized in that the structure includes a cast-in-place pile placed in the permafrost layer and an inner A heat pipe of working medium is provided; the lower evaporation section of the heat pipe is buried in the cast-in-place pile, and the upper condensation section is set between the ground surface and the building; the upper part of the heat pipe is provided with a radiator.

Compared with the prior art, the present invention has the following advantages:

1. The lower evaporation section of the heat pipe of the present invention is buried in the cast-in-place pile, the upper condensation section is arranged between the surface and the building, and the upper part of the heat pipe is provided with a radiator. When the heat pipe works, the working medium is cooled to the outside in the condensation section. The air releases heat and then cools down and liquefies. The liquefied low-temperature working medium flows down to the evaporation section to absorb the heat of the pile foundation and its surrounding permafrost, and then heats up and evaporates to the condensation section of the heat pipe. This process occurs repeatedly in the heat pipe until the temperature of the evaporation section is close to or higher than the temperature of the condensation section. The temperature of the pile foundation and the permafrost layer in which the pile foundation is located can be significantly reduced by means of the working characteristics of the heat pipe, thereby preventing the pile foundation from settling.

2. The present invention has a simple structure and is easy to implement.

Description of drawings

The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

FIG. 1 is a schematic structural diagram of the present invention.

FIG. 2 is a working principle diagram of the heat pipe in the present invention.

In the figure: 1—permafrost layer; 2—cast-in-place pile; 3—surface; 4—building; 5—heat pipe; 6—radiator; 7—working medium.

Detailed ways

As shown in Figures 1 and 2, a structure of a cast-in-place pile combined with a heat pipe to cool the frozen soil in a permafrost region includes a cast-in-place pile 2 placed in the permafrost layer 1 and a working medium 7 inside. the heat pipe 5. The lower evaporation section of the heat pipe 5 is buried in the cast-in-place pile 2 , and the upper condensation section is arranged between the ground surface 3 and the building 4 ; the upper part of the heat pipe 5 is provided with a radiator 6 .

The heat pipe is a device that realizes one-way heat conduction by utilizing the principle of evaporating heat absorption and liquefying heat release of the working medium, and is widely used in subgrades in permafrost areas. In the construction stage of the pile foundation, after the drilling is completed, one or more heat pipes 5 are tied to the steel cage and placed in the drilled hole for concrete pouring to complete the construction of the cast-in-place pile 2. The lower evaporation section of the heat pipe 5 is buried in the existing pile. In the cast-in-place pile 2 , the upper condensation section of the heat pipe 5 is between the ground surface 3 and the building 4 . The upper condensing section is exposed to the air, and a radiator 6 is added to the exposed condensing section to improve the heat dissipation efficiency. The number and length of the heat pipes 5 are determined according to calculation.

When the heat pipe 5 is working, the working medium 7 in the heat pipe 5 absorbs heat in the evaporation section of the heat pipe 5 and evaporates into a gaseous state to the condensation section of the heat pipe 5, and at the upper part of the heat pipe 5, the heat radiated by the radiator 6 returns to a liquid state and flows to the evaporation section through the inner wall of the heat pipe 5. . After such a circulation process, heat is continuously transported upward, forming a unidirectional heat conduction from bottom to top, and part of the heat in the cast-in-place pile 2 and its surrounding permafrost layer 1 is carried to the air above the surface 3 , let the permafrost layer 1 achieve the cooling effect. The permafrost layer 1 will not melt when kept at a low temperature, thereby ensuring that the foundation of the building 4 or other engineering foundations will not be unevenly deformed and cause damage to the building 4 and the like.

Example The Chinese Academy of Sciences Qinghai-Tibet Plateau Beiluhe Permafrost Engineering and Environmental Comprehensive Observation and Research Station (located in the hinterland of the Qinghai-Tibet Plateau, 34°51.2'N, 92°56.4'E, 4628 meters above sea level) is located in a permafrost area, housed in 2017 Part of the pile foundation in the construction process adopts the invention: the diameter of the pile foundation is 0.8m, the length of the pile is 10m, the length of the heat pipe evaporation section is 8m, the length of the condensation section is 2.2m, the length of the finned part is 1.4m, the width of the fins is 19mm, and the distance between the fins is 10mm. . In the first cold season after the completion of the building, the maximum temperature difference between the side temperature of the heat-containing pipe pile at a depth of 4m and the natural site temperature can reach 2.61°C, that is, the temperature of the side of the heat-containing pipe pile at a depth of 4m is 2.61°C lower than that of the natural site. , it can be seen that the heat-containing pipe pile foundation has a significant cooling effect.

Claims (1)

1. A structure in which a cast-in-place pile in a permafrost region is combined with a heat pipe to cool the frozen soil, wherein the structure comprises a cast-in-place pile (2) placed in the permafrost layer (1) and an internal construction The heat pipe (5) of the quality (7); the lower evaporation section of the heat pipe (5) is buried in the cast-in-place pile (2), and the upper condensation section is arranged between the surface (3) and the building (4) ; The upper part of the heat pipe (5) is provided with a radiator (6).

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